Thermoregulation & thermal stress Flashcards
What is a humans normal resting core temperature?
36.5–37.5°C
In the heat, core temperature can safely increase up to ? degrees C.
40 degrees C
In the cold, core temperature can safely drop to ? degrees C.
35 degrees C
What is body core temperature defined as?
Temperature of the hypothalamus, the thermoregulatory centre of the body
How can core body temperature be assessed?
Oesophageal temperature
Rectal temperature
Stomach temperature (swallowed telemetry pill)
Oral temperature
Tympanic temperature
What range is skin temperature usually at?
32-35°C
What is cool, warm, and hot mean skin temp?
cool = <30 degrees C
warm = 30-34.9 degrees C
hot = >35 degrees C
Name 4 effectors of temperature regulation.
- adrenal medulla (releases epinephrine)
- sweat glands
- skin arterioles
- skeletal muscles
Describe the physiological control of thermoregulation in hot conditions.
body temp increase, afferent info to brain, efferent information causes blood vessels to dilate, sweat glands secrete fluid (heat is lost) - body temp returns to normal
Describe how heat is conserved/produced.
- shivering thermogenesis
- voluntary muscular activity
- non-shivering thermogenesis
Describe how heat is lost.
- Blood reaching the skin
- Sweating
What happens when performing aerobic exercise in hot environment?
- Increase demand on heat loss mechanism (skin blood flow and sweating)
- Reduced gradient between core and skin - therefore core temp increases
How does dehydration exacerbate heat stress impacts?
Decreases sweat rate and plasma volume.
- Further ↓ cardiac output, maximal oxygen uptake, muscle strength and work capacity
Why is prolonged HIE markedly impaired by a hot environment?
-Competing regulatory demands for blood flow between thermoreg, working muscle and CNS
-Heat-related changes in skeletal muscle function and metabolism
What is the most rapid way to lower body temp?
Cold water immersion
